Speaking to Ann Curry on NBC this morning, attorney Gerald
Shargel refused to provide any details as to what Halderman's
defenses will be, but, giving a name-dropped Dan Rather, he did
say that
Halderman's colleagues are shocked that he's involved.
Halderman is a man of "impeccable reputation, highly
regarded in the industry," Shargel said. "He's innocent."

Shargel may simply be trying to get a bit of a handle on the bad
press by putting a public face on his client's defense -- better
to have someone out there saying you are innocent than no one at
all.

But, in saying this is "out of character" and that people who
know Halderman are shocked could also be Shargel laying the
groundwork for an insanity defense.

In New York, the defendant has the burden to prove insanity.
He must prove that, as a result of mental disease or
defect, he did not possess "substantial capacity either to
appreciate the criminality of his conduct or to conform his
conduct to the requirements of the law."

It is extremely difficult to convince a jury that a defendant,
especially an educated, well-connected one like Halderman appears
to be, that they did not understand that their actions were
criminal. Further, extortion is not a crime that takes place in
an instant -- the defendant would have to show that he was
incapable of understanding that what he was doing during the
various steps it took to complete it.

Convincing a jury that he was legally insane when he was
writing the letter, gathering his evidence, approaching and
meeting with Letterman and then cashing the check the next day is
requesting a pretty big leap of faith.

None of the above actions alone mean that he was not insane, but
considering the available information, it would be an extremely
difficult defense to argue successfully. It will be
interesting to examine his attorney's statements for future clues
as to whether Halderman will pursue such a risky strategy.